Apparatus for smelting ores



IN V EN TOR.

March 26, 1957 w so 2,786,665

APPARATUS FOR SMEILTING ORES 2 Sheets-Sheet 1 pflli i arroe/va s March 26, 1957 o. F. SWENSON 2,736,665

APPARATUS FOR SMELTING ORES Filed June 9, 1954 2 SheetsSheet f? NEH /5 m E s: F

. M i w I p &. Blame-e 4 M A;

I INVENTOR. 05642 A SWENSOA/ United States Patent APPARATUS FOR SMELTING ORES Oscar F. Swenson, South Pasadena, Calif.

Application June 9, 1954, Serial No. 435,401

3 Claims. (Cl. 263-27) This invention relates to a method and apparatus for smelting ores.

A primary object of the invention is to provide an improved method and apparatus for smelting ores wherein fuels such as crude oil, producer gas, natural gas or illuminating gas may be used eifciently and effectively.

Another object of the invention is to combine with a smelting furnace a preheater into which crushed ore may be fed. The preheater is connected to the smelting furnace in such a manner that hot gases from the smelting furnace can be caused to pass through the preheater and through the crushed ore therein so as to effectively conserve heat and preheat the'ore before it is fed from the preheater into the smelting furnace itself. With this arrangement the heat used to smelt the ore in the smelting furnace is most economically and advantageously employed.

Still another object of the invention is to provide an apparatus which is of such design as to have a low first cost of installation per ton of ore to be smelted, a low fuel smelting cost per ton of molten metal produced, economical operation, and low maintenance cost with relatively few, if any, moving parts that are exposed to high temperatures. By means of the present method of apparatus relatively small smelting units can be installed producing as low as only fifty tons of molten metal per day with economical operation and requiring little, if any, water other than for water cooling purposes. This enables smelters embodying the present invention to be installed in remote desert locations closely adjacent to the ore supply requiring only that fuel and possibly fluxes to be transported to the smelter and the smelted metal to be transported therefrom. By the use of such fuels as crude oil, producer gas, natural gas or illuminating gas, a better grade of metal is frequently obtainable in that objectionable impurities usually introduced into the metal along with coke, when coke is used as a fuel, can be avoided.

With the foregoing and other objects in view, which will be made manifest in the following detailed description and specifically pointed out in the appended claims,

reference is had to the accompanying drawings for an out, indicates generally a smelting furnace which can be erected on a suitable foundation or base structure indicated at 11. This furnace can be erected of any preferred refractory material of the type usually employed in the construction of smelters. The side walls and top are preferably double-walled, the walls being indicated at 12 and '13, respectively, providing an air space 14 therebetween through which incoming air may be drawn for the dual purpose of air cooling the inner walls 12 and being preheated thereby.

At one end of the furnace 10 there are one or more burners 15 through which fuel is fed into the furnace. This fuel may be crude oil, producer gas, natural gas or illuminating gas, or the like. The interior of the furnace is so shaped as to cause the smelting metal to collect as at 16 for withdrawal through a normally plugged outlet 17 that is covered by a door 18. Slag floating on top of the molten metal may be withdrawn through a normally plugged outlet 19 normally covered by a door 20.

The interior of the furnace is traversed by an inclined arch 21 located intermediate between the top and bottom of the furnace and terminating short of the forward wall of the furnace. This arch tends to direct flame and heat from the burner 15 downwardly onto the pool of molten metal in the furnace and functions as a hearth on which preheated ore can be fed into the furnace.

As illustrated in the drawings at the top and back of the furnace there is a preheater generally indicated at 2% This preheater is somewhat in the nature of a tower divided into one or more compartments, only three of which have been illustrated, these being indicated at 23, 24 and 25. The number of compartments may be increased or decreased from the number shown. The lower compartment communicates with the interior of the furnace 10 through a perforated wall 26. The bottom of the compartment 25 is perforated, as indicated at 27, and in a similar manner the bottom of the compartment 25 is perforated, as indicated at 28.

An inlet pipe or conduit 29 leads into the uppermost compartment 25 and through this pipe crushed ore may be fed into the uppermost compartment. An overflow pipe or conduit 30 which extends upwardly a short distance into the compartment 25 and extends downwardly into the compartment 24 serves to conduct ore from compartment 25 to compartment 24. In a similar manner a pipe or conduit 31 leads from the compartment 24 above the bottom thereof to the smelting furnace 10. This pipe may have a branch inlet 32 through which fluxes, if necessary, may be introduced into the preheated ore as it passes from the preheater into the smelting furnace. By means of this arrangement, heated gases developed or generated Within the smelting furnace 10 are caused to pass through the perforated wall 26 into the compartment 23 and then pass upwardly in a sequential manner into the compartments 24 and 25. Upward flow of these gases is permitted by the perforations 27 and 28 in the perforated bottoms of the compartments. An outlet for these gases is provided at 33 which preferably discharges into a cyclone separator before passing to the stack 34.

Such cyclone separator is indicated at 35 and the outlet 36 therefrom may be conducted to tailings.

The space 14 between the inner and outer walls 12 and 13 is covered at one end thereof remote from the air inlet by means of a cover 37 (see Fig. 2) and this cover is connected to a power driven blower 38. The outlet from the blower is branched, one branch being indicated at 39 and the other indicated at 40. The branch 40 extends into the furnace over the fire box therein and then extends forwardly to the front of the furnace where it is connected to a water cooled tuyere indicated at 41. This tuyere causes the air that has been highly heated in the branch 40 to be discharged rearwardly onto the top of the arch 21. 42 indicates a nozzle through which reducing agents, such as, for example, hydrogen may be discharged into the furnace toward the top of the arch 21, if this is necessary. The other branch 39 leading from the blower 38 may be itself branched and be discharged into the com-' partments 23 and 24,- such as are indicated by the outlets 43and44. The operation and advantages of the above-described .ncccssary. may be extended into each of the compartments and into possess Qqustruction.areisuhstantiallyas follows. If the raw masda .i are th are i stashed dry sash as b a ball mill to a particle size of 15 mesh or smaller. The fines of the crushed ore may be as fine as 300 mesh par- .Q fi :;DS ifi l I- "Ihi Q' h er es ths wit t e sa-ry flux material, such as crushed lime stone a ge fet iit to the zp sh ate th o gh h inle p n o Q. 1 .2 a are .di cha d o t the bot m o h compa tmen 5- Hot gases from the furnace 1t whi c;l1;are caused to pass upw rd y thr ugh t e per a ns 2 keep hi c u h ore in ya stateof suspension or an'rnation while passing therethrough. As these gases pass-through the crushed ore-ahighly etlicient heat transfer takesp lat so that the c ush d m te ia i h sc-mmrimn 2 i h ed t a temperature of approximately 690 F. or higher. As the c u he .02 is bein co t nu us i st t th preheater throu th in e pipe .2 this rte-he e an im cru her e ov flow int th top .Q P n 0 a d pa dow wa dly .the s hrws t b d ha i t the lower compa m n .2 n t s wmpartmcm o ch t gases from the furnace 10 passing upwardly through the perforations 27 alsokeep the ore in asta te ofsuspension or animation and raise the temperature of the ore to a temperature of about 1000 ,F. or to a-point just below that temperature to which the ore would change to sponge.

As'the overflow from compartment 25 to compartment 24 is also continuous, overflow from compartment 24 :takes place through the outlet pipe 31. In the course of its passage through this pipe additional fluxes may be added, if necessary, through the branch 32. The preheated ore falls from the passage 31 onto the arch 21 where it first attains a sponge form and then is reduced to molten condition, flowing and falling from the arch into the pool of molten metal 16. if it is necessary to reduce the ore, reducing agents, such as hydrogen, can be ied into the furnace 1G and directed against the arch 21 through the nozzle 42 from a suitable source of supply.

Air required for the smelting and preheating is furnished from the tuyere .41 and as this air has been preheatedas it passes through the space 14 and through the branch pipe 46 its temperature on discharge from the tuyere will normally be over l000 F.

Molten metal is tapped regularly through the outlet .17 and slag may be periodically tapped from the furnace from the outlet 19. The volume of heated air discharged through the tuyere or through the outlets 43 and 44 can be regulated or controlled by dampers arranged in the two branches 39 and 40, which dampers have not been shown. By regulating these dampers temperature control can be regulated to a large extent.

As the gases from the furnace-pass upwardly through the ore in the compartments 2S and 24 and keep the bed of orein these compartments constantly in a turbulent or agitated condition, an emcient heat transfer is effected. This also tends to reduce the danger of localized overheating. The air pressure in the chambers 23 and 24 is regulated with respect to the depth of the bed so as to igeep the bed of ore ineach chamber or compartment in a turbulent condition. The compartments of the preheater are equipped with suitable manholes, as well as peepholes. The peepholes may enable the contents of the "compartments to be inspected as occasion may require and the manholes permit the compartments 25 and 24 to be cleaned out at the time of'shutdowns, if this becomes Sui-table temperature indicating instruments the furnace wherever it is desired.

While 1. have illustrated the preheater as being mounted upon and arranged directly over the smelting furnace, which is preferable in small installations, it will be understood that the preheater may be arranged in side by side i elationsh-ip to the smelting furnace if desired, it being merely necessary to provide a suitable connection for conducting heated gases from the smeltingfu nace to-the preheater.

"The invention as above described .has been explained with relation to the smelting of iron ores which may be of relatively low grade and remotely located in desert areas. Where the smelter is remotely located near the deposit of ore, it is merely necessary to transport to the smelter the fuel requirements and fluxes or reducing agents necessary.

While the invention has been described in connection with the smelting of iron ore, 'it will be appreciated that it may bensed equally .well andwith equal advantage on other ores.

Particular advantages to be gained by the improved smelter are a low first cost installation per tonof ore to be treated, a low fuel smelting cost per ton of molten metal, the ability to control ;-the .heatfduring the various steps of the operation, the elimination of the introduction of objectionable impurities which are introduced into the metal with other fuels, and reducing agents such as coke, the obtaining of a better grade of metal due to the ability to control temperaturesfand the ability to economically operate the .smelters even where the installation is of relatively small capacity. The improved smelter'has a relatively low operating cost, even enlarge size unit installations and practically no movingparts are exposed to any high temperatures. The maintenance cost is consequently relatively low and as little, if any, water is requ ired other than for the purpose of cooling the tuyere Al, :the installation may be set up in desertareas where water. is practicallyunavailable.

Various changes may be madc in the details of construct-ion without departing from the spirit and scope of the invention as defined by theappended claims.

I claim:

1. {in apparatus for smelting ores comprising a furnace having a depression in its bottom in which molten metal may collect, means by which the metal may be tapped from said depression, an inclined arch extending partially over said depression, heating means arranged beneath the arch for heating the furnace, a preheating tower, means for feedingor i to the tower, there being one or more supporting perforated partitionsin the tower on which the ore may be supported, means for conducting products of combustion fromthe furnace up through the partitions and ore supported thereon in the tower to preheat the ore, andmeans for conducting the preheated ore from the tower and discharging itonto the arch.

2. An apparatus for smelting ores comprising a furnace having a depression in its bottom in which molten beneath the arch for heating the furnace, a preheating tower, meansfor feeding ore into thetower, there 'being one or more supporting perforated partitions in the tower on which the ore may be supported, means for conducting products of combustion from the furnace up through the partitions andoresupported thereon inthe tower to P fl 3 9 me n o sqndus ins h pr h t a t am the t e and dis har in 'Qn t et h said furnace be n d uble-W l d wi th s ac be en th walls having an air inlet, tuyeres in the inner wall of the furnace directed against said arch, anda conduit arranged to receive heated air from between the walls conducted adjacent the heating means and discharge itthrough the tuyeres against the arch.

3. An apparatus for smelting ores comprising a furnace havinga depression in its bottom in which molten metal may collect, means by which the metal may be tapped from said depression, aninclined arch extending partially oversaid depressions, heati ng mean arranged beneath the arch for heating the furnace, a preheating tower, means forfeeding ore into .the tower, there being n .m su s tins perforated pa ti gn lath tower wh ch t are m be su o t mean t r sosdu ;ing products of combustionfromdhe ,furnaceup through the partitions and ore supported thereon in the tower to preheat the ore, means for conducting the preheated ore from the tower and discharging it onto the arch, said furnace being double-walled with the space between the walls having an air inlet, tuyeres in the inner wall of the furnace directed against said arch, a conduit arranged to receive heated air from between the walls, said conduit being branched with one branch conducting air adjacent the heating means and discharging it through the tuyeres against the arch the other conduit discharging air received from between the walls into the preheating tower beneath the perforated partitions therein.

References Cited in the file of this patent UNITED STATES PATENTS Renton Oct. 24, 1854 McNair Apr. 1, 1884 Brett Sept. 30, 1884 Kirk Dec. 10, 1901 Gronwall et al Mar. 15, 1932 Bauer Nov. '7, 1950 White Feb. 5, 1952 

